Correct : c

Explanation:
1. Evaluate Option (a): The passage states "every one must have reflected how primeval...", using the word "reflected" to mean thought or deeply considered. It does not mention carrying a physical mirror. (Incorrect)
2. Evaluate Option (b): The text specifies that the author "planned to write a book of poems entirely about the things in my pocket," not a poem about epics themselves. (Incorrect)
3. Evaluate Option (c): The text explicitly and literally states: "...the pocket-knife, for instance the type of all human tools, the infant of the sword." This perfectly matches the statement. (Correct)
4. Evaluate Option (d): The author states that his intended book of pocket-poems would be "too long" and notes that "the age of the great epics is past." He does not define epics as being inherently "inconvenient" to write. (Incorrect)